Linux - Networking - Revision history

NickPGSmith: /* DHCP Server (DHCPD) */

2025-12-24T07:52:40Z

DHCP Server (DHCPD)

← Older revision		Revision as of 07:52, 24 December 2025
Line 89:		Line 89:

	-v option can be useful for debugging.		-v option can be useful for debugging.

			== DCP Client ==

			To send hostname to server, in /etc/NetworkManager/conf.d/dhcp-hostname.conf
			[connection]
			ipv4.dhcp-send-hostname=yes
			ipv4.dhcp-hostname=owl

	== DHCP Server (DHCPD) ==		== DHCP Server (DHCPD) ==

NickPGSmith: /* NFS */

2025-07-01T07:06:03Z

NFS

← Older revision		Revision as of 07:06, 1 July 2025
Line 862:		Line 862:

	and then run:		and then run:
	/usr/sbin/exportfs -a		/usr/sbin/exportfs -av

	to syncronise the current exported list /var/lib/nfs/etab to it.		to syncronise the current exported list /var/lib/nfs/etab to it.

			Reexport (sync with /var/lib/nfs/etab)
			/usr/sbin/exportfs -rv

	On client:		On client:

NickPGSmith: /* Milter */

2025-05-13T06:18:37Z

Milter

← Older revision		Revision as of 06:18, 13 May 2025
Line 794:		Line 794:
	smtpd_milters = unix:/run/clamav-milter/clamav-milter.socket		smtpd_milters = unix:/run/clamav-milter/clamav-milter.socket

	Combine this with other milters (Spamassassin, opendkim etc), commma-separated.		Combine this with other milters (Spamassassin, opendkim etc), commma-separated. For outgoing mail scanning, see:
			smtpd_milters = ...

	=== Dovecot (POP and IMAP) ===		=== Dovecot (POP and IMAP) ===

NickPGSmith: /* Milters */

2025-05-13T06:17:41Z

Milters

← Older revision		Revision as of 06:17, 13 May 2025
Line 543:		Line 543:
	Enabling mail filters ([https://www.postfix.org/MILTER_README.html milters]), by adding different TCP or Unix sockets to milters in a list (processed in order):		Enabling mail filters ([https://www.postfix.org/MILTER_README.html milters]), by adding different TCP or Unix sockets to milters in a list (processed in order):
	smtpd_milters = unix:/run/opendkim/opendkim.sock, unix:/run/spamass-milter/postfix/sock, unix:/run/clamav-milter/clamav-milter.socket		smtpd_milters = unix:/run/opendkim/opendkim.sock, unix:/run/spamass-milter/postfix/sock, unix:/run/clamav-milter/clamav-milter.socket
			and these will be used for incoming messages.

	Mail submitted outside of smtpd can be handled with:		Mail submitted outside of smtpd (outging messages) can be handled with:
	non_smtpd_milters = ...		non_smtpd_milters = ...

NickPGSmith: /* DKIM */

2025-05-13T05:56:48Z

DKIM

← Older revision		Revision as of 05:56, 13 May 2025
Line 670:		Line 670:
	ausearch -c 'smtpd' --raw \| audit2allow -M my-smtpd		ausearch -c 'smtpd' --raw \| audit2allow -M my-smtpd
	semodule -i my-smtpd.pp		semodule -i my-smtpd.pp

			and for outgoing processing:
			ausearch -c 'cleanup' --raw \| audit2allow -M my-cleanup
			semodule -X 300 -i my-cleanup.pp

	Config:		Config:
	* /etc/opendkim.conf (see [http://www.opendkim.org/opendkim.conf.5.html here])		* /etc/opendkim.conf (see [http://www.opendkim.org/opendkim.conf.5.html here])


	Sign outgoing messages, and verify incoming:		Sign outgoing messages, and verify incoming:
Line 712:		Line 715:
	The RSA private key is generated in default.private (ensure it is owned by opendkim user), and the default.txt contains the DNS TXT record that should be published by DNS with name "default._domainkey".		The RSA private key is generated in default.private (ensure it is owned by opendkim user), and the default.txt contains the DNS TXT record that should be published by DNS with name "default._domainkey".

	Test the key:		Test the key, requiring DNS to return the public key TXT record:
	opendkim-testkey -d your-domain.com -s default -vvv		opendkim-testkey -d your-domain.com -s default -vvv

	~~A key security problem here will be due to lack of DNSSEC.~~

	Enable/start opendkim service		Enable/start opendkim service
Line 721:		Line 722:
	systemctl start opendkim		systemctl start opendkim

	To enable Postfix to ~~communicated~~ with DKIM for ~~main sending~~, add this to /etc/postfix/main.cf		To enable Postfix to communicate with DKIM for mail receiving, add this to /etc/postfix/main.cf:
	smtpd_milters = unix:/run/opendkim/opendkim.sock		smtpd_milters = unix:/run/opendkim/opendkim.sock

			For sending:
			non_smtpd_milters = unix:/run/opendkim/opendkim.sock

	and restart postfix. Check resultant header added to incoming email:		and restart postfix. Check resultant header added to incoming email:

NickPGSmith: /* General */

2025-05-12T19:59:09Z

General

← Older revision		Revision as of 19:59, 12 May 2025
Line 450:		Line 450:
	* [https://www.mail-tester.com/ www.mail-tester.com]		* [https://www.mail-tester.com/ www.mail-tester.com]
	* [https://mxtoolbox.com/diagnostic.aspx Open Relay Test]		* [https://mxtoolbox.com/diagnostic.aspx Open Relay Test]
			* Get automated report by sending to: check-auth@verifier.port25.com

	Terminology:		Terminology:

NickPGSmith: /* DKIM */

2025-05-12T19:26:36Z

DKIM

← Older revision		Revision as of 19:26, 12 May 2025
Line 667:		Line 667:
	ausearch -c 'opendkim' --raw \| audit2allow -M my-opendkim		ausearch -c 'opendkim' --raw \| audit2allow -M my-opendkim
	semodule -X 300 -i my-opendkim.pp		semodule -X 300 -i my-opendkim.pp
			ausearch -c 'smtpd' --raw \| audit2allow -M my-smtpd
			semodule -i my-smtpd.pp

	Config:		Config:

NickPGSmith: /* DKIM */

2025-05-12T19:05:41Z

DKIM

← Older revision		Revision as of 19:05, 12 May 2025
Line 661:		Line 661:
	DomainKeys Identified Mail: the sender MTA signs message with a private key; the corresponding public key is in a DNS record and verifies the message and some headers have not been changed since signing.		DomainKeys Identified Mail: the sender MTA signs message with a private key; the corresponding public key is in a DNS record and verifies the message and some headers have not been changed since signing.

	* Install: opendkim opendkim-tools		Install:
	* Config: /etc/opendkim.conf (see [http://www.opendkim.org/opendkim.conf.5.html here])		* opendkim opendkim-tools

			Check SELinux rules allow opendkim service to write to /run/opendkim/opendkim.sock:
			ausearch -c 'opendkim' --raw \| audit2allow -M my-opendkim
			semodule -X 300 -i my-opendkim.pp

			Config:
			* /etc/opendkim.conf (see [http://www.opendkim.org/opendkim.conf.5.html here])


	Sign outgoing messages, and verify incoming:		Sign outgoing messages, and verify incoming:

NickPGSmith: /* General */

2025-04-27T17:20:23Z

General

← Older revision		Revision as of 17:20, 27 April 2025
Line 465:		Line 465:
	* 465/TCP (SMTPS):		* 465/TCP (SMTPS):
	** [https://tools.ietf.org/html/rfc8314#section-3 Implicit TLS], now recommended instead of STARTTLS on 25/TCP.		** [https://tools.ietf.org/html/rfc8314#section-3 Implicit TLS], now recommended instead of STARTTLS on 25/TCP.

			NOTE In Fedora 42, MTA is in /usr/bin/sendmail but some MUA still look in /usr/sbin, so can link:
			ln -s /usr/lib/sendmail.sendmail /usr/sbin/sendmail

	=== Postfix ===		=== Postfix ===

NickPGSmith: /* Milter */

2025-04-27T16:19:56Z

Milter

← Older revision		Revision as of 16:19, 27 April 2025
Line 760:		Line 760:
	#Example		#Example
	MilterSocket /run/clamav-milter/clamav-milter.socket		MilterSocket /run/clamav-milter/clamav-milter.socket
	ClamdSocket unix:~~/var~~/run/clamd.scan/clamd.sock		ClamdSocket unix:/run/clamd.scan/clamd.sock
	MilterSocketMode 660		MilterSocketMode 660
	AddHeader Add		AddHeader Add